Body fluid flow control method and device

ABSTRACT

An implantable apparatus for controlling fluid flow within a host body includes a constricting member for allowing fluid flow within a body canal when in an open position, and for reducing fluid flow within a body canal when in an closed position. Remote telemetry can be used to operate the constricting member from a position outside the body. The constricting member can include a piston having at least two protrusions for contacting the vessel surface of the body canal. A fluid-operated member can receive fluid to reduce fluid flow within the body canal and expel fluid to allow fluid flow within the body canal. An actuating member is provided for operating the fluid-operated member between the open and closed positions. The actuating member has structure for flowing fluid into and out of the fluid-operated member. A control device is provided for operating the actuating member. An implantable drive mechanism for a constricting member or other medical device includes a sealed housing for implantation in a patient body, a drive magnet positioned within the housing, an actuator for moving the drive magnet, and a magnetically susceptible drive member positioned outside the housing such that movement of the drive magnet within the housing will move the drive member outside of the housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part application of U.S. patent applicationSer. No. 09/965,762, filed Sep. 28, 2001 now U.S. Pat. No. 6,689,046,which itself is a continuation-in-part application of U.S. patentapplication Ser. No. 09/676,336, filed Sep. 29, 2000 now U.S. Pat. No.6,527,701;

FIELD OF THE INVENTION

The invention relates to an implantable medical device and a method forthe control of fluid flow through a body host canal or vessel, such as aurethra.

BACKGROUND OF THE INVENTION

Incontinence is a condition wherein persons lose control over theirvoluntary urinary function. The condition can arise from various causes,which include a variety of related and unrelated diseases, aging, anddeterioration of the voluntary urethra sphincter muscle. The cost andinconvenience to persons suffering from this condition are great.Several remedies exist that are known in the prior art. Among these, themost common are surgical corrections both minor and major, drugs,devices and diaper capture systems which serve to capture discharges.Another solution is to place a patch over the urinary orifice to preventunwanted discharge. Possibly, the most effective solution to date is theuse of an artificial sphincter. This device is surgically installed andis hydraulically or pneumatically driven, operating by inflation ofballasts to suppress fluid flow. However, control of this device issometimes difficult and is often inconvenient. Throughout the full rangeof the available treatment alternatives, the levels of efficacy, usefullife, and complications vary greatly, with none of the current treatmentalternatives being particularly effective in especially severe cases.Accordingly, there is a need for an improved apparatus to control theloss of voluntary urinary function.

SUMMARY OF THE INVENTION

The present invention overcomes and alleviates the above-mentioneddrawbacks and disadvantages in the art through novel implantable bodyfluid flow control devices for the control of fluid flow through a hostbody canal or vessel, such as a urethra.

Generally speaking, and in accordance with a first aspect of theinvention, an implantable apparatus for controlling fluid flow within ahost body comprises a constricting member for allowing fluid flow withina body canal when in an open position and for reducing fluid flow withina body canal when in a closed position, an actuating member foroperating the constricting member between said open and closedpositions, and control means for operating said actuating member.

Preferably, the constricting member comprises a first engaging elementand a second engaging element for coupling to the first engaging elementto encircle a body canal. At least one of the first engaging element andthe second engaging element preferably has apertures to allow tissuegrowth therethrough from and to the surface of the body canal. A lockingmember is preferably provided for locking the first engaging element andsecond engaging element into the locked position.

The constricting member preferably comprises a plunging member moveablesuch that the plunging member may apply pressure against said body canalto compress said body canal into said closed position. The actuatingmember preferably comprises a connector having first and second ends.The first end of the connector is preferably attached to said plungingmember and is axially moveable by said control means to move saidplunging member.

The actuating member may comprise a housing whereby the second end ofthe connector extends slidably through an aperture in the housing and iscoupled to an actuator provided in the housing, for example physicallyor by way of magnetic fields, such that movement of the actuator resultsin movement of said plunging member away from the body canal to allow atleast some fluid flow therethrough. The actuating member preferablycomprises a motor operatively coupled to the second end of the connectorso that activation of the motor causes the second end of the connectorto be axially pulled towards the motor resulting in movement of saidplunging member away from the body canal to allow at least some fluidflow therethrough.

A trigger mechanism is preferably provided for activating the motor. Thetrigger mechanism may be a magnetically operated switch, aradio-controlled circuit, a manually operated button implanted under thepatient's skin, or any other suitable trigger mechanism. A manualoverride system may also be included. The manual override system mayinclude a magnet that can be used outside the patient's body.

A second aspect of the invention provides an implantable apparatus forcontrolling fluid flow within a host body comprising a constrictingmember for restricting fluid flow within a body canal when in a closedposition, and for allowing fluid flow within the body canal when in anopen position; a control mechanism for controlling movement of theconstricting member between said open and closed positions; and a linkmember linking the constricting member and the control mechanism suchthat the constricting member and the control mechanism are implantablein different parts of the host body.

The control mechanism can be separable from said link member so thatsaid control mechanism may be replaced without removal of theconstricting member or the link member from the host body.

Preferably, the link member is adapted for moving said constrictingmember between said open and closed positions so as to alter fluid flowwithin the body canal, and an actuating member is preferably providedfor actuating said link member. The link member may be a cable providedin a protective sleeve, or may be any other suitable link between theconstricting member and the control member such as a wire carryingelectronic control signals, a wireless radio communication system, etc.

The actuating member and the control mechanism are preferably providedin a housing separate from the constricting member. The actuating memberis preferably a motor, most preferably with a remotely operated triggermechanism, for example, a magnetically operated trigger mechanism, foractivating the motor or magnetic unit from a position outside thepatient's body.

The motor or magnetic unit preferably acts through a worm gear.Preferably, the worm gear defines an axis, and the link member isattached to a casing, the worm gear co-operating with a threadedaperture provided in said casing in order to move said casing in adirection parallel to the axis of the worm gear.

According to another aspect of the present invention, there is provideda seal for an elongated link member, the link member extending betweenan implantable apparatus for implantation in a host body and a controlmechanism. The link member extends through an opening in a housing. Theseal includes a tubular membrane having two openings, one opening beingsealed to the housing, the other opening being sealed to the link membersuch that fluid entering the housing around the link member is trappedby the membrane. The membrane flexes to allow movement of the shaft.

The membrane is preferably sealed to said link member by gripping meansextending around the membrane and the shaft. The gripping means maycomprise a coil. The membrane preferably comprises a bellows that foldsinwardly when the link member is moved axially away from an interior ofthe housing, and expands when the link member is moved axially into thehousing. The bellows may include a reinforcing ring so that folding ofthe bellows may be controlled.

According to yet another aspect of the invention, there is provided anoperating mechanism for a constricting member for controlling fluid flowin a body canal. The constricting member is actuable between open andclosed positions. The operating mechanism includes an axially moveablelink member operatively connected to the constricting member foractuating the constricting member. Operating means are provided foraxially moving the link member. A coupling for selectively transmittingthe axial movement is connected between the link member and theoperating means.

The coupling acts so that in one direction there is positive engagementbetween the operating means and the link member, whereas in an otherdirection, some play is allowed between the operating means and the linkmember. The coupling may be used so that opening of the body canal maybe achieved by direct actuation of the operating means acting on thelink member, but on closing of the body canal, the coupling preventspressure being directly applied to the body canal by the operatingmeans, thus reducing the likelihood of damage to the body canal.

The coupling may include magnets or a compressible member. A magnet maybe attached to the link member, and at least one other magnet may beattached to the operating means. The magnets may be physically moveabletowards and away from each other, or they may be electromagnets suchthat they may be operated when required. The compressible member may beprovided in a moveable casing. The link member may be operativelyconnected to the compressible member, the motor acting to move thecasing, and the compressible member acting to move the link member.Alternatively, the coupling may include chain links or a jointedextensible framework, or other means of preventing direct application ofpressure to the body canal.

In the case of a coupling comprising magnets, a manual override systemmay be included, which manual override system comprises a further magnetoperable from outside the patient's body. The manual override magnetshould be of sufficient strength to move the magnet attached to the linkmember against the magnetic force of the magnet attached to theoperating means.

Another aspect of the invention provides a method of controlling fluidflow within a host body. The method includes implanting a constrictingmember around a body canal, the constricting member reducing fluid flowin the body vessel when in a closed position. The method furtherincludes implanting a control mechanism in the host body; and providingand implanting a link member between the constricting member and thecontrol mechanism to allow the control mechanism to control theconstricting member. The control mechanism may be removed from the hostbody and replaced without removal of the constricting member and thelinking member.

The constricting member may include engaging elements defining anopening therebetween, the method including surrounding the body canalwith the engaging elements so that the body canal extends through theopening.

The method may further include suturing the engaging elements to thevessel. In addition, the control mechanism may be implanted remote fromthe body canal.

Yet a further aspect of the invention includes a remote telemetry systemfor an implantable apparatus, the telemetry system including a signalingmechanism capable of sending and receiving signals to and from a controlunit implanted in a host body in order to monitor the operation of theimplantable apparatus, the telemetry system being capable of alteringoperating settings of the implantable apparatus.

The signals are preferably electromagnetic radiation, most preferablyradio signals. The implantable apparatus may include sensors to monitoractions of the implantable apparatus on the host body, and the telemetrysystem would include a mechanism to interrogate the sensors to providefeedback on the sensed data. Preferably, the sensors are capable ofmonitoring pressure exerted by a moveable part of the implantableapparatus on a part of the host body, the feedback on the sensed dataincluding commands to alter the range of movement of the moveable partof the implantable apparatus.

Another aspect of the invention includes an implantable apparatus forcontrolling fluid flow in a host body. The implantable apparatusincludes a constricting mechanism including a reciprocable member forselectively applying pressure to a canal of the host body in order toselectively constrict the canal. A pressure sensor is included fordetecting the pressure applied by the reciprocable member to the canal.A feedback system is also included for altering movement of saidreciprocable member in response to the pressure sensed by said pressuresensor in order to prevent damage to said canal.

The object and advantages of the implantable fluid flow control devicesof the present invention permit implantation and use without severingthe canal or vessel to be constricted. Moreover, because trauma isminimized with respect to the canal or vessel, and the devices of thepresent invention are relatively small, lightweight and made ofcorrosion-resistant material, such as durable plastics, titanium orstainless steel, the devices are suitable for use for extended periodsof time to control fluid flow through numerous types of vessels tocontrol, for example, urination, defecation, ejaculation, nutritionabsorption for control of obesity, etc. Splitting the fluid flow controldevice and its control box also provides significant advantages. Thesurgery to implant the fluid flow control device is delicate andinvolved, whereas the surgery to implant the control box is much lessinvolved as the control box may be implanted in an easily accessibleplace, just under the skin of the patient. Thus, when any part of thecontrol box fails, the control box may be removed and replaced with anew control box without needing to adjust the fluid flow control device.The replacement of the control box does not therefore need to be done bya specialist surgeon, and may be performed in a large number ofhospitals or even physicians offices under local anaesthetic. Thesurgery is thus much less traumatic for the patient and may be performedin a location that is convenient for the patient rather than in ahospital that is able to perform specialized urological surgeries.

An implantable apparatus for controlling fluid flow within a host bodyincludes a constricting member for allowing fluid flow within a bodycanal when in an open position, and for reducing fluid flow within abody canal when in a closed position. The constricting member comprisesa bladder. The bladder receives fluid to reduce fluid flow within thebody canal and expels fluid to allow fluid flow within the body canal.An actuating member operates the constricting member between the openand closed positions. The actuating member comprises structure forflowing fluid into and out of the bladder. Control means is provided foroperating the actuating member.

The constricting member preferably comprises an engaging element forsubstantially encircling a portion of the canal. The bladder ispositioned in the constricting member such that expansion of the bladderupon receiving the fluid will cause the bladder to compress the canalagainst the engaging element to reduce fluid flow within the body canal.The actuating member can comprise a pump, a fluid reservoir, and a fluidconduit connecting the fluid reservoir with the bladder. The pump movesfluid between the reservoir and the bladder.

The pump can comprise a flexible transfer conduit and an impeller forcompressing the fluid transfer conduit and thereby pumping fluid fromthe fluid transfer conduit. At least a portion of the fluid transferconduit is preferably arcuately disposed. A portion of the pump impellermoves arcuately along the fluid transfer conduit to compress the fluidtransfer conduit and pump fluid from the fluid transfer conduit. Theimpeller can comprise a plurality of radially disposed rollers. Therollers can be mounted on a drive disk rotated by a motor to move therollers arcuately along the fluid transfer conduit for compressing thefluid transfer conduit. The motor direction is reversible such that in afirst direction the pump will move fluid into the bladder, and in asecond direction the pump will withdraw fluid from the bladder. Thefluid can be any suitable fluid, including liquids such as water orgases such as air.

A telemetry system according to the invention is provided forcontrolling the operation of the constricting member. The telemetrysystem preferably comprises structure for sending and receivingelectromagnetic signals which code for operating commands for theactuator. The signals can be a coded series of pulses such as short andlong pulses. The pulses are received by suitable receivers andinterpreted by suitable logic structure to translate the pulses intocommands or information that is useful for maintaining or operating thedevice. The commands or information is then used to operate the motor orother features of the invention.

These and other objects, features and advantages of the presentinvention may be better understood and appreciated from the followingdetailed description of the embodiments thereof, selected for purposesof illustration and shown in the accompany drawings. It should thereforebe understood that the particular embodiments illustrating the presentinvention are exemplary only and not to be regarded as limitations ofthe present invention. In particular, the illustrated embodiment relatesto an artificial sphincter for a urethra, but it should be understoodthat the device can be used with any body fluid flow canal or vessel.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, advantages and features of the presentinvention, and the manner in which the same are accomplished, willbecome more readily apparent upon consideration of the followingdetailed description of the present invention taken in conjunction withthe accompany drawings which illustrate a preferred and exemplaryembodiment, and wherein:

FIG. 1 is a front exploded view of a body fluid flow control deviceaccording to the invention;

FIG. 2 is a side exploded view of the body fluid flow control device ofFIG. 1;

FIG. 3 is a partial side view of the device of FIG. 1 in the closedposition;

FIG. 4 is a partial front view of the device of FIG. 1 in the closedposition;

FIG. 5 is a side exploded view of a control box and device for use witha body fluid flow control device;

FIG. 6 is a partial top view of the control box and device of FIG. 5;

FIG. 7 is a partial cross-sectional view of a motorized activatingmember for use with the device of FIG. 1 in the open position;

FIG. 8 is a partial cross-sectional view of the motorized activatingmember of FIG. 7 in an intermediate position;

FIG. 9 is a partial cross-sectional view of the motorized activatingmember of FIG. 7 in the closed position;

FIG. 10 is a top partial cross-sectional view of an alternativeembodiment of control box and device;

FIG. 11 is an enlarged cross-sectional view of the joint between thecable and link member of FIG. 10;

FIG. 12 is a partial cross-sectional view of an alternative embodimentof motorized actuating member;

FIG. 13 is a top partial cross-sectional view of yet a furtheralternative embodiment of control box and device;

FIG. 14 is a partial cross-sectional view of the control device of FIG.13;

FIG. 15 is a partial cross-sectional view of an alternative means ofconnecting a link member to a body fluid flow control device; and

FIG. 16 is a partial cross-sectional view of a further alternative meansof connecting a link member to a body fluid flow control device.

FIG. 17 is a schematic diagram of a fluid operated implantable apparatusfor controlling fluid flow within a host body.

FIG. 18 is a schematic diagram, partially broken away, of a pumpimpeller assembly.

FIG. 19 is a perspective view of a telemetry control device according tothe invention.

DETAILED DESCRIPTION OF THE INVENTION

By way of illustrating and providing a more complete appreciation of thepresent invention and many of the attendant advantages thereof, thefollowing detailed description is given concerning the novel implantablebody fluid control device and uses thereof.

Referring now in more detail to the drawings, in which like numeralsrefer to like parts throughout several views, FIGS. 1–4 show a bodyfluid flow control device according to the present invention. The bodyfluid flow control device comprises a first engaging element 102 and asecond engaging element 104. When the first engaging element 102 iscoupled with the second engaging element 104, an inner diameter isformed which is suited for fitting around a host body canal, i.e., anytube or vessel V within the human or animal body, such as the urethra.

The body fluid flow control device also comprises a locking mechanism106 for locking the first and second engaging elements 102 and 104together. The locking mechanism 106 may be of any suitable form. In theillustrated embodiment, locking mechanism 106 is in the form of lockingpins 108 located on the first engaging element 102 and locking holes 110located on the second engaging element 104. In the illustratedembodiment, two locking holes 110 are provided on each side of engagingelement 104. Each locking pin 108 is capable of being attached to eitherof the locking holes 110. The inner diameter formed between parts 102and 104 may thus be adjusted for use with different sized vessels. Itshould be understood that any other equivalent locking mechanism can beused for this purpose. Alternative locking mechanisms contemplated bythe present invention include, but are not limited to, the use of astrap and snap pins or interconnecting molding on the first and secondengaging elements 102 and 104.

The body fluid flow control device of the present invention preferablyfurther includes a piston-like or plunging member 112 located within theinner diameter formed by the coupling of the first and second engagingelements 102 and 104 such that the plunging member 112 may applypressure against a body canal or vessel, such as a urethra. As can beseen most clearly from FIGS. 2 and 15, plunging member 112 may have acurved profile such that only outer edge protrusions of the plungingmember contact the vessel surface in use. This substantially reduces thelikelihood of necrosis of the tissue of the vessel because it allowspressure to be placed on the vessel over a smaller area than would bepossible with a flat plunging member. The curved profile of plungingmember 112 may be provided on a removable plunger head, so that asurgeon may select an appropriately sized plunger head for the size ofthe vessel.

It should be appreciated that the fluid flow control device may takeother forms than that illustrated. For example, instead of a plungingmember provided in two engagement members, one of the engagement memberscould be moveable with respect to the other to compress the vessel inorder to restrict fluid flow therein. Alternatively, a fluid flowcontrol device in the form of an artificial external annular sphincteror other means for compressing the vessel may be applied to the vessel.

Apertures 113 may be provided in first engaging element 102. Theapertures 113 permit tissue growth therethrough from and to the surfaceof the vessel in order to anchor the body fluid control device onto thevessel. Further apertures (not shown) may be provided to allowdissolvable sutures to be used to secure the engaging element to thevessel on a temporary basis, until the engaging element is completelyanchored in place by the tissue growth. Alternatively, the material ofthe engaging element may be such as to allow suturing therethrough, orthe engaging element may be otherwise attached to the vessel. It hasbeen found that tissue growth is achieved within a few weeks ofimplantation of the device into a host body and so it may also bepossible to implant the device without any form of attachment to thevessel, and to simply let the tissue growth firmly attach the device tothe vessel over time.

All components of the device are made from biologically inert andcompatible materials. For example, the fluid flow control device may bemade of polypropylene, silicone, titanium, stainless steel and/orTeflon.

An actuating member is utilized by the body fluid flow control device ofthe present invention to bias the plunging member 112 to apply pressureagainst the body vessel when the body fluid flow control device is inthe closed position, and to pull the plunging member 112 away from thevessel to open the device. The actuating member may comprise a cable 114covered by a protective sleeve or sheath 116, the cable 114 having afirst end 118 and a second end 120. Cable 114 is preferably a braidedstainless steel cable, although any suitable material may be used.Protective sleeve 116 is preferably made from a bio-compatible materialhaving non-stick properties to discourage tissue growth thereon. Asuitable material is Teflon. The cable 114 may be slidably moveablewithin sleeve 116, or cable 114 and sleeve 116 may be slidably moveabletogether.

The first end 118 of the cable 114 runs slidably through an aperture(not shown) in the second engaging element 104 and is attached to theplunging member 112. A collar 122 is provided around the sleeve 116where it passes through the aperture in the second engaging element 104,in order that any tissue growth on and around second engaging element104 does not interfere with the movement of sleeve 116 through theaperture, if the sleeve 116 is designed to move with cable 114. If cable114 is slidably moveable within sleeve 116, collar 122 prevents tissueingress into the end of sleeve 116.

FIGS. 5–9 illustrate a control box for the fluid flow control devicethat is connected to end 120 of cable 114. The control box comprises ahousing 202, a motor 204 having a worm gear 206, a spring 208 andbellows 210 to provide a seal around sleeve 116. The housing 202 may bemade of polypropylene or any other suitable biologically inert material.Batteries 212 are also provided, which should preferably be suitable forimplantation in the body, such as batteries manufactured by WilsonGreatbatch Ltd, of Clarence, N.Y., USA. An operating mechanism (notshown) may be provided in the control box, or may be implantedseparately in the host body in an easily accessible place.

The arrangement of the control box and cable 114 allows the control boxto be implanted in the body separately from the fluid flow controldevice. For example, the control box may be implanted close to thepatient's skin in their abdomen, with the cable 114 and sleeve 116extending from the control box 202 to the fluid flow control device thatis implanted around the urethra or other body vessel.

Cable 114 is attached at end 120 to a nut 216 which is located in theinterior of a slidably moveable casing 214 in housing 202. Spring 208 isalso located within casing 214, which has a threaded aperture 218 toallow worm gear 206 to pass into the interior of casing 214.

Spring 208 is interposed between the motor 204 and cable 114 in order toprovide a coupling for selectively transmitting axial movement from themotor 204 to the cable 114 and hence to the body vessel V, the operationof which is described with reference to FIGS. 7 to 9 below. In theillustrated embodiment, the motor 204 acts on casing 214 to move spring208 and cable 114 by means of the nut 216. However, any suitablecompressible member may be used in the casing 214 to cushion the vesselfrom the action of the motor, for example, a resiliently deformablematerial may be used, or a compressible fluid such as a gas could beused if casing 214 was suitably sealed. Alternatively, a spring or othercompressible member may be connected directly to or inserted in cable114. Such an arrangement would preferably use a compressible member thatwas stiff enough so that pushing and pulling motions were still impartedto the cable 114 on operation of the motor.

The slidable casing 214 and worm gear 206 allow axial movement to beimparted to cable 114 by motor 204, but it should be appreciated thatany suitable axial actuation of cable 114 may be used. For example, themotor 204 may have an axially moveable actuator, or suitable gearingcould be provided to act on a toothed rack or other axially moveableelement. Alternatively, the cable could have a flexible end that may bewound around an axle in housing 202.

The sleeve 116 containing cable 114 should be sealed to housing 202 toprevent ingress of body fluids from damaging the motor and othercomponents of the control box. Any suitable seal may be used, but itshould be noted that where sleeve 116 is designed to be slidablymoveable, it is not possible to seal tightly around sleeve 116, as thesleeve needs to be axially moveable in order to impart movement toplunging member 112. One method of sealing sleeve 116 to housing 202 isto use a bellows mechanism. A suitable bellows mechanism 210 isillustrated in FIGS. 7–9. Bellows 210 is designed so that as sleeve 116moves axially, bellows 210 expands or collapses in on itself so thatfluid that seeps into housing 202 around sleeve 116 is captured bybellows 210, and can be forced back out of the housing 202 when thedevice is moved to a closed position.

The sleeve 116 may be sealed to bellows 210 and housing 202 by means ofa threaded bolt 220, and a nut 222. Bolt 220 is passed through anaperture in housing 202 with its head 224 in the interior of thehousing. Sleeve 116 passes through and is a close fit with a centralbore 226 in bolt 220. Bellows mechanism 210 is generally tubular and issealed to the underside of head 224 of bolt 220 by an O-ring seal 228.As the nut 222 is tightened on bolt 220, compression of the O-ring seal228 causes a tight seal to prevent ingress of fluid into housing 202around the exterior of bolt 220. Bellows 210 extends around the head 224of bolt 220 and is sealed to sleeve 116 in the interior of housing 202by a tightly wound spring 230. The spring 230 may be placed onto thebellows 210 before the sleeve 116 is forced through the bellows 210 andspring 230 in order to obtain the tightest seal possible. Other methodsof sealing bellows 210 to sleeve 116 include cable clamps, C-clips,adhesive, etc. A reinforcing ring 234 is provided on one surface ofbellows 210, to ensure that the bellows 210 collapses correctly as thesleeve 116 is moved axially. The reinforcing ring 234 may be a thickenedarea in the wall of the bellows 210, or may be a separate ring that isattached to the bellows, by gluing or any other suitable means. Instead,or in addition to, the reinforcing ring 234, the bellows may be pleatedor folded in order to ensure correct folding when the fluid flow controldevice is moved to the closed position.

It should be noted that bellows 210 can be of any suitable shape,provided that a seal is made at the housing and around the sleeve, andthat bellows allows movement of the sleeve into and out of the housing.For example, bellows 210 may be a simple tubular shape, with ends of thetube being sealed to the housing and sleeve. Alternatively, bellows 210may be of a frusto-conical shape, or a more complicated shape such as abell-shape or could be folded or pleated. The seal to the housing couldbe close to the aperture in the housing through which the seal extends,as illustrated, either inside the housing or outside the housing.Alternatively, the seal could be made to the wall of the housing, aroundor behind the bolt 220.

It is possible to seal the sleeve 116 and the housing 202 without usinga bellows mechanism, but it has been found that energy losses arecreated as movement of the sleeve 116 creates friction against the seal.This can cut the battery life of the motor by up to ⅓. For example, aflexible annular ring may be sealed between the sleeve 116 and thehousing 202, the annular ring stretching as the sleeve is axially moved.Alternatively, a series of seals may be provided along sleeve 116, eachseal preventing some fluid ingress to housing 202.

Control circuitry (not shown in FIGS. 7–9) is provided, which operatesthe motor on receipt of a signal from an operating mechanism. Any of theseveral well-known control devices can be used to control the operationof the body fluid flow control devices of the present invention by auser so long as the objectives of the present invention are notdefeated. Suitable operating mechanisms include radio-control devices,or a magnetic devices that can be sensed by the control circuitry. Witha magnetic device, the user may be provided with a separate magnet thatthey carry with them, and which they position adjacent the skin over theimplanted switch when they wish to operate the device. The magnet may beof any suitable shape, and may be shaped for example like a pen orcredit card so that its purpose is not immediately apparent to otherpeople. The magnet should have a weak magnetic field so that it must beplaced close to the switch in order to operate the device, in order toprevent accidental operation of the device if the magnet is carried in apocket. Alternatively, a touch sensor, infrared, voice or soundactivation may be used, or a manually operated switch may be implantedunder the skin of the patient.

A remotely operated operating mechanism is preferred because the devicecan be operated without irritation to the skin, as would happen with amanually operated trigger. In the preferred embodiment, a manualoverride switch may be provided in addition to the remotely operatedtriggering mechanism. The manual override switch is designed to be usedtemporarily if the control box fails and the user is not close to aphysician's office or hospital to have the control box changed. Themanual override switch may be provided in the control box, and may besealed from the interior of the control box until the first activationof the switch, for example by a membrane seal. Such a use of the manualoverride switch may eventually allow fluid ingress into the control box,which may then need to be replaced. Alternatively, no manual overrideswitch may be provided, which would mean that the user would have to useincontinence pads until the control box could be replaced.

The control circuitry controls operation of the motor, and may detectthe position of the plunging member, for example, via the position ofthe casing or via the drag exerted on the motor. Preferably, the controlcircuitry also monitors the level of charge in the battery. The controlcircuitry can be used to initiate opening or prevent closing of thefluid flow control device if a problem such as low battery or adefective motor is detected, so that the device can be caused to remainin the open position. For example, once the device has been opened, anabutment (not shown) may be caused to contact the casing 214 to preventany further movement thereof The motor may also be shut off. The devicemay still be operable by a manual override, as the spring 208 can becompressed and allowed to expand within casing 214 to allow movement ofthe cable 114 to open and close the device.

The control box 202 may also contain components that allow a physicianto interrogate the control circuitry by a remote telemetry systemwithout accessing the box itself. Such components may be interrogatedand/or controlled by radio waves or other interactive signalstransmitted and received by the telemetry system, or any other suitablemechanism. This allows the physician to check the charge in thebatteries, any internal sensors, to alter the tension in the cable 114,and to make other suitable adjustments. A pressure sensor may beprovided on the plunger 112 to monitor the pressure between the plunger112 and the vessel V when the plunger is in the closed position. Thepressure sensor may also be interrogated by the telemetry system, whichcan then be used to alter the settings for the control device. Forexample, the number of turns that the motor 204 causes worm gear 206 tomake on each operation of the device may be altered in order to set thecorrect distance of travel of the cable 114, and hence plunger 112 forany particular patient so as to alleviate any excess pressure exerted onthe vessel V. In addition, the telemetry system may include controlcommands to cause the motor to open and close the body fluid flowcontrol device, either as an override system to the normal operatingmeans, or in addition to the normal operating means in order to test thedevice in situ.

If the control box causes the device to fail or remain in the openposition if a problem is detected, this will simply mean that thepatient will return to the condition that they were in beforeimplantation of the device, in other words, in a condition ofincontinence. If the device failed in the closed position, the patientwould need to be catheterized. However, a manual override system wouldallow the patient to operate the system manually for a considerableperiod of time or until medical aid was obtainable.

Actuation of the device is described with reference to FIGS. 7 to 9. Inthe open position shown in FIG. 7, the motor 204 has operated the wormgear 206 to draw casing 214 towards the motor 204. This pulls nut 216along with the casing 214, and thus acts on cable 114 to pull theplunging member 112 away from the vessel V. Bellows 210 is also at itsfully extended position. In order to close the fluid control device, themotor 204 is activated to turn worm gear 206 in the opposite directionto that used to open the device. As worm gear 206 is operated, casing214 is moved away from the motor 204, spring 208 pushing on nut 216 tobias plunging member 112 against the vessel V, as shown in FIG. 8. Asthe motor 204 is operated further, the vessel V prevents plunger 112moving, and prevents movement of cable 114 and hence nut 216, due to theincreased force needed to move cable 114 against the vessel V when thevessel V is already closed. Nut 216 presses against spring 208, causingcompression of the spring 208, as shown in FIG. 9. It can thus be seenthat any further movement of worm gear 206 by motor 204 does not resultin compression and injury of the vessel V, but the further compressionof spring 208. In this way, axial movement of casing 214 may beselectively transmitted to cable 114. This protects the vessel V againstfailure of the device by continuous running of the motor 204, as thevessel cannot be further compressed due to the interplay between thevessel V and the spring 208.

An alternative embodiment of the control box is illustrated in FIGS. 10and 11. The control box comprises a housing 902, a motor 904 having aworm gear 906, a spring 908 and bellows 910. Batteries 912 are alsoprovided, along with control circuitry (not shown). The spring 908 islocated in a slidable spring casing 914. An operating mechanism (notshown) may be provided in the control box, or may be implantedseparately in the host body in an easily accessible place. The spring,worm gear and motor arrangement are as described for FIGS. 5–9, and willnot be further described.

Housing 902 is preferably formed in two pieces, a main body 916 and anend lid 918. End lid 918 includes a lip 920 that fits inside an end 922of main body 916. A groove 924 is provided around lip 920, in order toreceive an O-ring 926. End lid 918 is also sonically welded to main body916 in order to provide a good seal. A groove 928 is provided around theexterior of end 922 of main body 916, in order to allow for ease ofremoval of lid 918 with a suitable tool when necessary. An interiorhousing 930 extends along the length of housing 902, to one sidethereof, in order to separate the motor 904, worm gear 906, slidablecasing 914, bellows 910 and other moveable parts from the batteries 912.Interior housing 930 has a flange 932 at an end 934 remote from end 922of main body 916, with an O-ring groove 936 provided in flange 932. Aset screw 938 is also provided in interior housing 930, in order to lockmotor 904. Electrical contacts 940 extend to motor 904 from end lid 918.An internally directed collar 942 having an internal thread extendsaround flange 932 within housing 902, and interior housing 930 issecured into housing 902 by means of an externally threaded nut 944which is screwed into place to hold flange 932 in position. Nut 944 mayhave pin holes 946 to allow for tightening thereof. An externallydirected collar 948 having an internal thread is also provided inhousing 902, in order to allow the cable 114 to pass into interiorhousing 930.

Sleeve 116 has an end 950 which is attached to a hollow connector 952having a first end 954 and a second end 956. At end 954, connector 952has backwardly-directed teeth 958 around the circumference thereof whichattach to the inside of sleeve 116 adjacent to end 950, and act toprevent sleeve 116 from being pulled loose. The second end 956 ofconnector 952 has an external thread 960, as well as a groove 962suitable for receiving an O-ring 964. Thread 960 is screwed into theinternal thread provided within collar 948 on housing 902. Cable 114extends into housing 902 through connector 952, and is attached at itsend 120 to a link member 966 which extends into casing 914 andterminates in nut 216. The connection between cable 114 and link member966 is shown enlarged in FIG. 11. The cable end 120 is fitted into aconnector piece 968 that has a tapered end 970 and a groove 972 forreceiving a sealing ring. Link member 966 has an opening 974 forreceiving connector piece 968, opening 974 having an internal shoulder976. A metal O-ring 978 is received by shoulder 976 and is held in placeby a ring retainer 980. Connector piece 968 is pushed into opening 974until the metal O-ring 978 seats in groove 972 to form a seal betweenconnector piece 968 and link member 966.

Bellows 910 are attached to housing 902 by means of nut 944 screwed intoinwardly directed collar 942. Bellows 910 has an end flange 982, whichextends adjacent to flange 932 of interior housing 930, and has anintegral O-ring 984 to seal in O-ring groove 936 of flange 932 so thatbellows 910 is tightly sealed to housing 902 by interior housing 930.Bellows 910 is also attached to cable link member 966 by means of acable link 986, and has a pleated conical shape above flange 982 so thatit may fold easily when compressed. It should be noted that in theembodiment of FIG. 10, the bellows 910 is not attached to the sleeve116, as the sleeve 116 is not axially moveable. Instead, cable 114 isaxially moveable within sleeve 116. In this embodiment, bellows 910 maynot be necessary, as a good seal may be provided between connector 952and control box 902. However, it is advantageous to provide anadditional seal, for example using bellows 910, to prevent fluid ingressinto control box 902.

The operation of the control box of FIG. 10 is the same as for thecontrol box of FIGS. 5 to 9, and will not be further described.

A further alternative embodiment of a seal for the sleeve and anactuator for the cable is illustrated in FIG. 12. In the illustratedembodiment, control box 1200 is completely sealed so that no fluidingress into the box can take place. A hollow cylindrical bore 1202 thatis sealed at one end 1204 is formed in control box 1200. Bore 1202 hasinternal threads 1206 provided adjacent an outer surface of control box1200.

An end of sleeve 116 is attached to a hollow connector 1208, connector1208 having an end 1210 and an end 1212. End 1210 of connector 1208 isdimensioned to pass into the end of sleeve 116, connector 1208 havingoutwardly and rearwardly directed teeth 1214 at end 1210 to engage theinterior of sleeve 116, thereby securing connector 1208 to sleeve 116.End 1212 of connector 1208 is dimensioned to be slightly larger indiameter than sleeve 116, and has external threads 1216. Connector 1208may be screwed into bore 1202 of control box 1200 by means of threads1216 and 1206.

End 120 of cable 114 is located in bore 1202, and is provided with acollar 1218. An annular magnet 1220 is supported by collar 1218 aroundend 120 of cable 114. Cable 114 is axially moveable within sleeve 116,and therefore a bellows seal is not necessary around sleeve 116. Inaddition, as sleeve 116 is not moveable, tissue growth around the sleevecannot affect the operation of the device.

A motor 1222 has a threaded worm gear 1224 engaged with a casing 1226through a screw-threaded aperture 1228 located in the bottom of thecasing. Casing 1226 extends around bore 1202, and an annular magnet 1230is supported around the interior of an upper edge of casing 1226. Magnet1230 is aligned with magnet 1220 located on end 120 of cable 114.

In order to actuate cable 114 to open and close the fluid flow controldevice, the motor 1222 operates the worm gear 1224, which moves casing1226 along the exterior of bore 1202. Magnet 1230 acts through theplastic material comprising bore 1202, and causes magnet 1220 to trackits movement. This in turn causes cable 114 to be axially moved,operating the fluid flow control device. If the motor 1222 continuesoperating the worm gear 1224 towards the cable 114 when the body vesselhas already been closed, the attraction of magnet 1220 for magnet 1230is not enough to cause the cable 114 to be moved further, due toresistance from the vessel walls, thus preventing potential damage tothe vessel. Thus, axial movement of casing 1226 is selectivelytransmitted to cable 114. In addition, the casing 1226 will come to restagainst bore 1202 or an interior surface of control box 1200, preventingthe magnets from getting too far out of alignment.

It should be appreciated that a magnetic link between the motor andcable may be achieved in many ways other than that illustrated in FIG.12. For example, the magnets need not be annular, but could be placed toone side of the cable. In addition, the magnets need not operate bymutual attractions, but could work by repelling each other to close thevessel, with a spring action or other means operating to open the vesselonce the motor-driven magnet was pulled back towards the motor. Also,the magnetic coupling does not require that the motor and the cable orother structure driven by the motor each have a magnet, so long as oneis magnetic and the other is capable of being moved by magneticattraction or repulsion. Electromagnets are also possible. With arepelling action, magnets could be placed directly on the ends of thecable and an axially movable actuator driven by the motor. It will beappreciated that the magnetic drive mechanism of the invention can beutilized to operate many other types of implanted medical devices otherthan constricting devices.

An alternative embodiment of a magnetic coupling for selectivelytransmitting axial movement to the cable is illustrated in FIGS. 13 and14. These figures illustrate a control box 1300 that is completelysealed. A bore 1302 having a blind end 1304 is provided in the controlbox 1300 for receiving the end 120 of cable 114. A connector 1306 isused to connect sleeve 116 to bore 1302. The connector 1306 has a firstend 1308 with rearwardly directed teeth 1310, a central shoulder 1312and a second end 1314 having external screw threads 1316. End 1308 ofconnector 1306 is pushed into the end of sleeve 116, the teeth 1310acting on the inner surface of the sleeve. End 1314 of connector 1306 isconnected to control box 1300 by means of an O-ring seal 1318 and aninternally threaded nut 1320 which is threaded onto threads 1316. Nut1320 is welded at 1322 to the control box 1300 to form a tight seal.

The cable 114 extends into bore 1302. A cylindrical magnet 1324 isattached to end 120 of cable 114 by a collar 1326 which is deformed ontothe magnet 1324 and cable end 120 for a tight fit. The control box 1300includes a motor 1328, a worm gear 1330 and batteries 1332 as describedfor the FIG. 10 embodiment. A casing 1334 having an annular magnetarrangement 1336 is threaded onto worm gear 1330, and operates in thesame manner as in the FIG. 10 embodiment so will not be furtherdescribed. Control circuitry including IC's 1338 and other standardcomponents 1340 including resistors and capacitors are also shown.

FIG. 15 illustrates an embodiment of a connector joining first end 118of cable 114 to the body fluid control device. Connector 1500 has afirst end 1502 having outwardly directed teeth 1504 which grip into theinner surface of sleeve 116. A second end 1506 of connector 1500 has acollar with inwardly directed threads 1508 which are threaded ontooutwardly directed threads 1510 on a collar 1512 attached to the bodyfluid flow control device. An O-ring 1514 forms a tight seal to thecollar 1512.

FIG. 15 also illustrates plunger 112 in detail. Plunger 112 includes aperforated metal bracket 1516 attached to a metal collar 1518. The mainbody of plunger 112 is formed of silicon that is molded onto theperforated bracket 1516, the silicon extending through the perforationsin the bracket to form a tight fit between plunger 112, bracket 1516 andcollar 1518. Metal collar 1518 may be simply crimped onto end 118 ofcable 118.

FIG. 16 illustrates a further alternative method of connecting cable 114and sleeve 116 to the body fluid flow control device. In the embodimentof FIG. 16, the fluid flow control device has a collar 1600 withinternal threads 1602. A connector 1604 is used to connect sleeve 116 tocollar 1600. Connector 1604 has external threads 1606, a central collar1608 and outwardly directed teeth 1610. It should be noted thatconnector 1604 may be the same as connector 1306 illustrated in FIG. 13.This allows for economies in manufacture, as only one type of connectorneed be provided for both ends of the sleeve 116. A metal collar 1612 isused to connect the plunger (not shown in FIG. 16) to end 118 of cable114. An O-ring 1614 may seal between collar 1612 and connector 1604.

There is shown in FIGS. 17–18 an implantable apparatus for controllingfluid flow within a host body. The apparatus includes a constrictingmember 1710 for allowing body fluid to flow within a body canal when inan open position and for reducing fluid flow within a body canal when ina closed position. The constricting member 1710 includes a bladder 1714.The bladder 1714 receives working fluid to compress the body canal andthereby reduce body fluid flow through the body canal, and expelsworking fluid to allow body fluid to flow again through the body canal.An actuating member 1720 is provided for operating the constrictingmember between the open and closed positions. The actuating member 1720includes structure for moving working fluid into and out of the bladder1714. This structure can include a pump 1724, as shown, having animpeller assembly 1728 and a motor 1730. A fluid transfer conduit 1734connects the pump 1724 with the bladder 1714. A reservoir 1740 can beprovided to store working fluid for operating the bladder 1714.

An engaging element 1744 can be provided for substantially encirclingthe body canal. Expansion of the bladder 1714 causes the bladder tocompress the body canal against the engaging element 1744 to reduce bodyfluid flow through the body canal. Expelling working fluid from thebladder permits the body canal to expand and body fluid to flow withinthe body canal. The engaging element 1744 can be of any suitable design.In the design shown in FIG. 17, the engaging element 1744 includes afirst piece 1750 and a second piece 1754. The first piece 1750 is joinedto the second piece 1754 by suitable connection structure (not shown).The bladder 1714 can be seated in an appropriate seat in second piece1750.

The bladder 1714 can be of different sizes and shapes, as well asmaterials. It is necessary that the bladder 1714 expand upon receivingworking fluid so as to constrict the body canal. Polymeric materialsthat are biocompatible can be utilized. The bladder material can be amaterial which stretches upon being filled with the working fluid, orcan be a flexible material. Alternatively, in place of a bladder otherfluid-operated structure can be provided, such as a rigid piston in achamber which is acted upon by the working fluid to move the piston andpress against the canal.

The pump for controlling working fluid flow through the fluid transferconduit 1734 to the bladder 1714 can be of many different designs. Thepump 1724 is preferably positioned within a suitable water-tight housingsuch as control box 1760. A pump conduit 1770 transfers fluid betweenthe reservoir 1740 and the fluid transfer conduit 1734. The pump 1724has structure for compressing the pump conduit 1770 so as to force theworking fluid through the pump conduit. In one embodiment, the pump 1724has an impeller 1728 which has a plurality of rollers 1764. The rollers1764 are provided adjacent to the pump conduit 1770 (FIG. 18). The pumpconduit 1770 is preferably provided along an arcuate housing 1774. Therollers 1764 extend outward from the surface of impeller 1728. In thismanner, rotation of the impeller 1728 causes the rollers 1764 tocompress the pump conduit 1770. Working fluid will thereby be drawn froma reservoir 1740, through a fluid inlet 1780, and into the pump conduit1770. The working fluid will be propelled by the compressing action ofthe impeller 1728 and rollers 1764 on the pump conduit 1770 through afluid outlet 1784 and into the fluid transfer conduit 1734. The workingfluid will travel through the fluid transfer conduit 1734 into thebladder 1714 so as to cause the bladder 1714 to expand and compress thebody canal. Compression of the body canal will restrict the flow of bodyfluid through the body canal. Other pump constructions are within thescope of the invention.

The motor 1730 is reversible such that in one flow direction workingfluid is caused to flow from the reservoir 1740 through the pump 1724 tothe bladder 1714. In the reverse direction, the pump 1724 will causeworking fluid to be withdrawn from the bladder 1714 and pumped into thereservoir 1740. The compression of the body canal will thereby bereleased and body fluid will be permitted to flow through the bodycanal. It is also possible that, in some constructions, reversal of thepump is not necessary to remove working fluid from the bladder 1714 andthat turning off the pump 1724 will cause the working fluid to drainfrom the bladder 1714. This is possible if the bladder 1714 is elasticor if there is a biasing on the bladder 1714 acting to return thebladder 1714 to the initial, non-expanded state. Appropriate valves orcheck valves can be positioned in the flow line to restrict or permitthe flow of working fluid as desired.

A telemetry system according to the invention provides appropriateinformation and commands to control operation of the actuator andconstricting member. There is shown in FIG. 19 a telemetry device 1910according to the invention. The telemetry device 1910 can include asuitable housing 1920. Within the housing 1920 is suitable circuitry forproducing telemetry signals which are transmitted to a control unitwhich controls operation of the actuator and the constricting device.The telemetry device 1910 can have an on/off power switch 1924. Suitableconnection ports or jacks can be provided such as power-in jack 1930 andearphones jack 1938. A display 1950 provides a visual indication ofoptions and telemetry information. A select button 1954 is provided toselect a function. A next button 1958 is provided to indicate differentfunctions. An electromagnet 1962 can provide a link to the implantedcontrol unit, and can be connected to jack 1966.

The telemetry device can be used to communicate with the control box andconstricting device to transmit a variety of information. The telemetrysignals can be utilized to initiate the device, to control itsoperation, and to recalibrate the device upon use. This information canrelate to the status of the control box and constricting device. Theinformation could also relate to the status of the patient, for example,body temperature. Telemetry commands can be particularly useful tocalibrate and set the position of the constricting member. For example,telemetry commands can be used to adjust the tightness of theconstricting member, to recalibrate to the starting point, to place insleep mode, to awake from sleep mode, or for special options, such asunit diagnosis, when the battery is low, or when there is no usage for aselected time. Other functions are also possible.

The telemetry device communicates with the control box using suitablecommunication protocols and coding. This coding can be in the form ofdifferent burst lengths of electromagnetic or magnetic radiation,similar to Morse code. An example of suitable control signals isindicated in Table 1. Other coding systems are possible, and can be usedto generate output in several different formats, such as text, bar codeor audio. Suitable logic circuitry or a microprocessor in the controlbox permits the translation of these control signals into operatingcommands for the motor, valves, or other structure in the device.

TABLE 1 PMD Telemetry Responses Error, PMD received unknown command orcould not perform the requested function *— — 6 turns; loosest *— 7turns; loose *— — — — 8 turns; normal default * 9 turns; tight *— 10turns; tightest *— Reclibrate started but not finished; must set 6, 7,8, 9, or 10 turns *— PMD disabled. PMD will respond only to check statuscommand and enable normal operation command. PMD will respond with errorto all others. — Enable normal operation. PMD will restore number ofturns in effect when it was disabled.   = short signal — = long signal *These codes can be signaled by the PMD when it receives a Check Statuscommand.

These telemetry signals can be any suitable signal such as magnetic,electromagnetic, acoustic, and any other suitable signals.

According to another aspect of the invention, an implantable apparatusfor controlling fluid flow within a host body comprises a constrictingmember for allowing fluid flow within a body canal when in an openposition and for reducing fluid flow within a body canal when in aclosed position. An electrically-operated actuator operates theconstricting member between the opened and closed positions. Controlstructure is provided for operating the actuator. The control structureincludes voltage measuring structure for controlling said constrictingmember. The voltage measuring structure can measures battery voltage.The voltage measuring structure can additionally or alternativelymeasure voltage drawn by the actuator. If battery voltage is low it isan indication of a drained or defective battery. If actuator voltage ishigh it is an indication that the actuator is drawing too much current,as would occur if the constricting member has met an obstruction ormechanical resistance. If a voltage irregularity occurs, the actuator iscaused to move the constricting member to the open position, so as topermit fluid flow through the body canal so as to avoid an accumulationof fluid in the body.

It will be understood that various embodiments of the present inventionhave been disclosed by way of example and that other modifications andalterations may occur to those skilled in the art without departing fromthe scope and spirit of the appended claims, such as, for example, thoseembodiments described in U.S. Pat. No. 6,319,191, issued Nov. 20, 2001,which is incorporated hereinto in its entirety by reference.

Thus, the invention described herein extends to all such modificationsand variations as will be apparent to the reader skilled in the art, andalso extends to combinations and subcombinations of the features of thisdescription and the accompanying figures. Although preferred embodimentsof the present invention have been illustrated in the accompanyingfigures and described in the foregoing detailed description, it will beunderstood that the present invention is not limited the embodimentsdisclosed, but is capable of numerous rearrangements, modifications andsubstitutions without departing from the spirit of the present inventionas set forth and defined by the following claims.

1. An implantable drive mechanism for an implanted medical device,comprising: a sealed housing for implantation in a patient body; a firstdrive member and a second drive member, at least one of said first drivemember and said second drive member being a magnetic field source, andthe other of said first drive member and said second drive member beingacted upon by said magnetic field such that movement of one of saiddrive members will cause movement of the other drive member; a first ofsaid drive members being positioned within the housing; an actuator formoving the first drive member; and a second of said drive members beingmovably connected to an exterior portion of the housing such thatmovement of the first drive member within the housing will move thesecond drive member outside of the housing.
 2. The implantable drivemechanism of claim 1, wherein said second drive member is operable todrive a constricting member for allowing fluid flow within a body canalwhen in an open position and for reducing fluid flow within a body canalwhen in a closed position.
 3. The implantable drive mechanism of claim1, wherein said first drive member is a magnet, and said second drivemember comprises a magnetically susceptible material.
 4. The implantabledrive mechanism of claim 1, wherein said housing comprises a bore sealedat one end, said second drive member being in part positioned in saidbore, said first drive member being provided in said housing adjacent tosaid bore.
 5. The implantable drive mechanism of claim 1, furthercomprising control structure for operating said actuator, said controlstructure being operated by a telemetry device from a position outsidethe patient body.
 6. An implantable drive mechanism for an implantedmedical device, comprising: a sealed housing for implantation in apatient body; a first drive member and a second drive member, at leastone of said first drive member and said second drive member being amagnetic field source, and the other of said first drive member and saidsecond drive member being acted upon by said magnetic field such thatmovement of one of said drive members will cause movement of the otherdrive member; a first of said drive members being positioned within thehousing; an actuator for moving the first drive member; and a second ofsaid drive members being positioned outside the housing such thatmovement of the first drive member within the housing will move thesecond drive member outside of the housing; and wherein said housingcomprises a bore sealed at one end, said second drive member being inpart positioned in said bore, said first drive member being provided insaid housing adjacent to said bore.
 7. An implantable drive mechanismfor an implanted medical device, comprising: a sealed housing forimplantation in a patient body; a first drive member and a second drivemember, at least one of said first drive member and said second drivemember being a magnetic field source, and the other of said first drivemember and said second drive member being acted upon by said magneticfield such that movement of one of said drive members will causemovement of the other drive member; a first of said drive members beingpositioned within the housing; an actuator for moving the first drivemember; and a second of said drive members being positioned outside thehousing such that movement of the first drive member within the housingwill move the second drive member outside of the housing; and controlstructure for operating said actuator, said control structure beingoperated by a telemetry device from a position outside the patient body.